Comparative Effects of a2 Skim Milk on Mild Cognitive Impairment in Older Adults

For inclusion in the study, participants must meet all of the following criteria:

• Adults aged 65-75 years;
• Complaint of memory loss for more than 6 months;
• Base on the Chinese version of Mini Mental State Examination (MMSE), cognitive ability score is lower than the standard cut-off value according to age and education levels: MMSE score≤ 17 points if years of education is 0 year; ≤ 20 points if 6 years or less of education; ≤ 24 points if more than 6 years of education
• Living and social functions are reduced: activities of daily living (ADL) score ≤18;
• Not meeting the diagnostic criteria for dementia (Diagnostic and Statistical Manual of Mental Disorders - Fourth Edition), Alzheimer Disease (National Stroke Institute for Neuropathic Speech Disorders and Association for Alzheimer Disease and Related Disorders); no mental disorder, brain damage, or other physical disorders that can lead to cognitive impairment.
• Agreed not to participate in another interventional clinical research study during the present study;
• Signed informed consent

Participants must be excluded from the study if they meet any of the following criteria:

• <65 years; or >75 years
• Neurological examination showed focal signs of central nervous system disorder such as hemiplegia, dysesthesia, aphasia; history of cerebrovascular diseases (including hemorrhagic and ischemic types), internal brain trauma or fracture;
• Asthmatic bronchitis, severe hypertension, angina and severe infection;
• Mental disorders such as depression and anxiety; endocrine system diseases (such as hyperthyroidism, hypothyroidism, systemic lupus erythematosus, rheumatoid arthritis);
• Newly diagnosed, progressing or advanced tumors;
• Visual, reading, hearing impairment or language communication difficulties that significantly affect cognitive function tests;
• History of alcohol dependence and abuse of psychoactive substances (e.g., antipsychotics, benzodiazepines, cholinesterase inhibitors, sedatives), or use of drugs that affect cognitive function;
• Neurological diseases (e.g. Parkinson's disease, epilepsy);
• Antibiotic treatment in previous 2 weeks;
• Administered immunosuppressive drugs in the 4-weeks preceding screening;
• Allergy to milk or dairy;
• Diagnosed lactose intolerance;
• Other diseases that investigators judged as unsuitable to participate the study.